I did a morning tour recently and really enjoyed it. The cooler temperatures and quieter desert made the experience much more comfortable, especially for dune bashing and taking photos at sunrise. If it's your first time, I'd recommend wearing light clothing, comfortable shoes, sunglasses, and bringing a bottle of water.
I compared several operators before booking and found that an Abu Dhabi desert safari with hotel pickup, camel rides, sandboarding, and dune bashing offered the best value. If you prefer sunsets, live entertainment, and a BBQ dinner, then the evening safari might be a better choice. But for a peaceful experience and great photography, I'd definitely choose the morning safari again.
